Viscosimeter



J. H. JONES VISGOSIMETER March 15, 1966 2 Sheets-Sheet 1 Filed Dec. 6.1963 INVENTOR JOHN HARRIS JONES ATTORNEY ermine! 2' 3' 4 IIOVA.C

68 Voltage Regulator United States Patent 3,240,053 VISCOSIMETER John H.Jones, 3701-13 W. Van Buren, Bellwood, Ill. Filed Dec. 6, 1963, Ser. No.328,611 Claims. (CI. 7357) The invention relates to devices or apparatusfor measuring the viscosity of fluids and is particularly adaptable formeasuring the internal fluid friction of blood emulsion.

It is a fact that in medical practice there is no satisfactory method ofchecking human blood viscosity and it is for this reason that Americanhospital laboratories do not make viscosity checks on blood specimens ofhospital or clinical patients.

The importance of blood viscosity as a diagnostic procedure is pointedout by August Reis in his report on the Kinetical Effect of IncreasedViscosity of the Blood (Zeitschrift fur innere Medizin 10, No. 14-,673-679, 1955). In his report in reference to such diseases as Addisonsdisease, thyreosis, cardiac ailments, depressive psychosis, he statesthat it was found time and again that the improvement of the clinicalpicture went hand in hand with the drop in blood viscosity. He furtherstates only by creating new instruments for checking viscosity will onebe placed in the position to correct pathological changes in energymetabolism, by acting directly upon the components of the chemicalresistance or the viscosity.

In regard to viscosity, Camerons Hydraulic Data states With fewexceptions viscosity is expressed as the number of seconds required fora definite volume of fluid under an arbitrary head to flow through astandardized aperture at constant temperature.

In Viscosity and its Measurement, Institute of Physics and the PhysicalSociety, Dinsdale & Moore, speak of the rate of shear and shearingstress" as affecting viscosity and of correcting for hydrostatic head,all of which calls for complicated mathematical formula.

Because of the difficulty of securing an exact constant head in presentday viscometers, the time consumed in doing this precludes their use forchecking !blood viscosities that must be checked immediately the bloodis withdrawn from the vein to be checked as close to an in vivo state aspossible.

Human blood is an emulsion being produced by the body by what may bedescribed as a continuous process. Many factors bear out the fact thatblood is continuously varying in physical character. One of thecharacteristics of blood emulsion is that its viscosity, along withother factors, would vary, and this invention was designed to helpmeasure blood viscosiy with the object of aiding diagnostic procedure.

To be relatively sure that the physical character of a blood specimen,after being removed from the circulation, would be comparable to thephysical character of the blood before it was removed from thecirculation, it is important that there would be a minimum of exposureto air and a minimum of time lapse between the securing of the bloodspecimen and the viscosity test.

The provision of a device or apparatus for measuring the internal fluidfriction of blood emulsion is the principal object of the invention. Theprovision of means for extracting a minimum amount of a blood specimenfrom the circulation and testing its viscosity with no or at "ice leastminimal contact of air with the specimen between the extraction of thespecimen and the test is another important object of the invention. Bythe use of my invention the test can be made within seconds after thewithdrawal of the blood specimen from the circulatory system, and thisis another important object of the invention, since blood emulsionundergoes rapid changes beginning from the moment it is withdrawn fromthe circulation and in direct proportion to its contact with ambientatmosphere. The viscosity is indicated by accurately measuring theelapsed time of the travel of a non-magnetic or austenitic stainlesssteel ball in the fluid between two sensing heads or proximity switchesperpendicularly spaced, the time being indicated immediately in secondsand hundredths of seconds on an electronic elapsed time counter.

I have invented apparatus and combinations of apparatus that eliminateall the objections found in the use of standard viscometers when usedfor checking human blood viscosities. My invention makes it possible tocheck human blood viscosities in less than one and one-half seconds,accurate to one one-hundredth of second, plus or minus.

In standard viscometers, such as Ostwald, blood is introduced into thetop of one leg of a U-tube up to a mark. The blood is then allowed toflow through a restricted aperture, the length of time being noted forthe blood specimens to pass through this aperture, the time of flowbeing affected by shearing stress, rate of shear and also continuousloss of hydrostatic head. The apertures of Ostwalds U-tube viscosimetersvary and this makes it necessary to standardize each Ostwald with asolution of known viscosity.

In my invention, instead of passing the blood down through an aperture,I establish an aperture and pass this aperture through a column ofblood. To accomplish this I use a specially constructed Pyrex glass tubeof five mm. inside diameter and an inside area of 19,635 sq. mm. Theaperture is established by introducing into the upper end of the Pyrexglass tube after it has been filled with human blood a non-magneticstainless steel ball. The circumference of this ball encloses an area of7.917 sq. mm. When the ball is introduced into the tube, itautomatically establishes a doughnut-shaped aperture of 11.718 sq. mm.

As the aperture descends through the column of blood, it passes twoaccurately spaced (16") magnetic sensing heads. The ball which ismaintained at the center of the aperture because of the exactperpendicularity of the viscosity tube, activates these sensing heads tostart and stop a visual counting device.

Because of the restrictive or braking elfect of. the restrictingaperture, the progress of the ball through the column of blood cannot bedescribed as free falling.

The exact size of the aperture is assured by the combination of thespecific inside diameter of the tube, 5 mm., and the specific diameterof the ball, 3.175 mm., the ball being spherically accurate to .0001.

Viscosity tests were made with my invention using US. Bureau ofStandards Oil D with 4 mm. ID. and 5 mm. ID. viscosity tubes. It will benoted that in the two viscosity tests of oil D, the oil being common toboth tests and the ball or bob also being common to both tests, that thedifference in the readings of the two tests was due solely to thedifference in the two apertures.

4 mm. I.D. tube (aperture 4.38 sq. mm.)

mm. I.D. tube (aperture 11.72 sq. mm.

Both columns read in hundredths of a second.

As before stated, there does not appear to have been any satisfactorytype of apparatus designed for clinical or hospital use in checkingtheblood viscosity of patients. While the importance of blood viscositydetermination has been recognized as a diagnostic procedure, the lack ofreliable apparatus for this purpose has severely limited this field ofmedicine. Therefore,-it is an object of my invention to provideapparatus for measuring or testing human blood viscosity which can beused to quickly and accurately provide data for clinical studies.

It is another object of my invention to provide apparatus which can beoperated by laboratory or hospital personnel after a relatively shortperiod of training.

It is a further object of my invention to provide electrical controlmeans in my apparatus whereby human errors in the test procedure arereduced to the minimum.

It is a still further object of the invention to provide apparatus formeasuring or testing human blood viscosity which can be readily movedabout in the facility where it is being used and conveniently pluggedinto outlets of the common 110 volt, 60 cycle, A.C. circuits.

In order to accomplish the above described objects, I provide a cartwhich can be easily wheeled about and which is designed to carry theviscosity measuring apparatus. At the top of the cart there is avertically mounted panel which carries a viscosity tube that is designedto receive the sample of human blood and associated means, which will bedescribed in detail later, for electrically timing the fall of a steelball through the column of blood in the viscosity tube in order tomeasure the viscosity of the blood. On this panel there is also mountedan electric timer with a large face and dials which can be easily readby a technician conducting the test. Necessary electrical switch meansfor the operators use are conveniently mounted on the panel and on thecart.

In general, my invention involves the use of an austenitic stainlesssteel ball release means disposed at the top of a perpendicularlymounted viscosity tube whereby the ball, that is machined to closetolerance, is allowed to fall under the influence of gravity through thecolumn of blood in the viscisity tube and past two sensing heads formingpart of an electrical sensing means. These heads are disposed inaccurately determined, vertically spaced positions on the viscositytube. The inside diameter of the viscosity tube is constant throughoutthe length of the tube so that as the steel ball falls through theblood, it, in effect, establishes an annular aperture for the relativeflow of blood past the ball. As the stainless steel ball passes eachsensing head, electrical signals are produced through the sensing meansand these signals are amplified to actuate relay mean for starting andstopping an electric timer. The elapsed time interval is noted by theoperator or technician and is used in computing or determining theviscosity of the blood sample.

Referring now to the accompanying drawings forming part of thisapplication, and wherein like reference characters indicate like parts.

FIGURE 1 is a perspective view of the invention.

FIGURE 2 is an enlarged cross-sectional view of the preferred viscositytube,

FIGURE 3 is an enlarged cross-sectional view of the ball applicator,taken on line 33 of FIGURE 1.

FIGURE 4 is a cross-sectional view somewhat enlarged on the line 44 ofFIGURE 1.

FIGURE 5 is a partial wiring diagram of a portion of the electricalsystem.

FIGURE 6 shows a wiring diagram of the electrical system used in myinvention.

Referring now more in detail to the drawing, it will be observed that Ihave provided a mobile table comprising a top 10 and a base section orcart 12 supported on caster wheels 14. Means are provided for levelingthe top 10, so that by adjustment of the table top, the viscosity tube,to be described later, can be arranged in a perpendicular position forthe test.

Leveling of the assembly on the cart 12 is accomplished by providing atripod assembly of three adjustable jacks or supports 11 upon which thetable top 10 rests. This top 10 is approximately 36 x 16 in size and hasinstalled therein a round bubble level 13 at the geometric center of thetop to assist the operator in leveling the top by adjustment of thejacks or supports 11.

A rectangular panel 15 about 20" x 30" in size is fixed in anyacceptable manner upon a table top. This panel is constructed of luciteor other electrically nonconductive material. One of the edges issecured to the table top in a manner so that the panel will bemaintained perpendicularly thereto. Spaced inwardly from one verticaledge of the panel a short distance is a pair of spring clips, indicatedat 16. Clips 16 are vertically spaced in axial alignment and areprovided as one simple means of removably holding the viscosity tube 18to the panel. It is important that the tube be held perpendicularly tothe table whenever my apparatus is being used to measure the viscosityof a sample of fluid.

The viscosity tube 18 is of Pyrex, 7 mm. outside diameter and 5 mm.inside diameter. The tube is provided at one end with an acute angledbend on a radius, the end of the tube being reduced in diameter toaccommodate one end of a rubber tubing of /s I.D. to be appliedthereover providing an airtight connection. The other end of the rubbertubing is provided with a spring clip closure.

The other end of the viscosity tube 18, a short distance from the topthereof, is provided with a bulb-like enlargement 62. On the panel a bobor ball feeder is indicated at 36 into which the top of the tube fits.This ball feeder 36, as will be seen from the enlarged sectional viewFIGURE 3, comprises a body portion with an axial hole 40 in one sidethereof which is applied over the upper end of the portion 34 of thetube. The hole 40 is in diameter slightly larger than the-outsidediameter of the portion 34. Connecting with this hole 40 is another hole42 of smaller diameter, which is equal to the inside diameter of theportion 34. At right angles to this hole 42 is a rectangular hole 44,laterally through the ball feeder, and this -is of like depth to that ofhole 42, but is of greater width. A slidable feeder bar 46 is applied inthis hole or slot 44-, which bar is provided with a pair of spaced holesES-48. These holes 4848 are registerable with other holes 50-50 of likediameter which communicate with larger hopper-like openings 52-52, eachof which holds a plurality of the spherical balls 54 used in making thetests. The feeder bar 46 is slidable back and forth within the limits ofthe operating knobs 56 on each end thereof so that when the bar 46 ismoved to the left, for example, the hole 48 would pass over the hole 42,during which movement one ball 54 would drop into the hole 42 and passdown through the viscosity tube. The balls are of austenitic nonmagneticstainless steel insuring that their rate of travel through the field ofthe sensing heads is not retarded, and are of a diameter just less thanthe internal diameter of the, viscosity tube 18.

When a ball 54 is dropped into the upper end of the tube 18, with theliquid to be tested filling the tube up to just about half way in theair release area 62, there would be a splash when the ball hit thefluid, which would cause any air bubble produced by the dropping of theball to escape to the upper level of the fluid before the ball reachedthe field of the upper sensing head. If the ball had any air bubblesentrapped ahead of its descent, a true reading of viscosity could not bemade.

When a test is to be made, the tube is filled with the fluid to betested until the bulb 62 is half filled. One operating knob is thenpushed so as to move the feeder bar 48 over hole 42 when a ball 54 woulddrop through openings 42 and 40 into the tube 18. Then as the ball dropsin the tube, it passes through the field of the upper sensing head 20,and starts the timer or counter 24 operating in a manner to be describedlater. As the ball continues its descent in the tube and passes throughthe field of the lower sensing head 20, it stops the counter 24. Theelapsed interval between the passing of the upper and lower sensingheads gives an indication of the viscosity of the fluid tested.

Referring to FIGURE 5, it can be seen that the cable leads, which aregenerally indicated at 64, from the sensing heads 20 of the sensingmeans are connected to terminals 1, 2' and 3 of a terminal strip 66. Thecomplete wiring of the terminal strip 66 is shown in FIGURE 6 of thedrawings but it is sufiicient at this point to note that this terminalstrip 66 also provides terminals for the 110 volt A.C. supply beingfurnished through voltage regulator 68, for an oscillator, amplifier andassociated relay assembly forming part of the sensing means andgenerally indicated at 2-2, and for electrical connections generallyindicated at 70, 72 and 74 to the electric timer 24 and indicating light26. The complete connections to terminal strip 66 are shown in FIGURE 6of the drawings.

The sensing means used with my invention is of the type which iscommercially available, and for my purposes I have used two sensingheads 28 together with an associated electrical system, generallyindicated at 22' and shown in FIGURE 6 as within the dash line box. Thissensing means, which is also known commercially as a proximity switch,is produced by Electro Products Company, Inc., of Chicago, Illinois. Thesensing means used in my invention is of the same general type as thatdisclosed in Reissue Patent No. 24,779, issued on February 9, 1960, toDavid L. Elam. It is not believed necessary to completely describe thefeature of the sensing means used in my invention, and for a completedescription of the mode of operation of this type of sensing means,reference is made to the above cited Reissue Patent No. 24,779.

In general, it can be stated that the heads 20' each includes astainless steel shell within which there is a wound inductance of finewire, and two leads from this inductance and a third lead attached to ametal clad cable 64 are carried to terminals 1', 2' and 3' on terminalstrip 66. Each head 20 and cable 64 in combination provide an inductanceand associated distributive capacity for a tuned circuit which isconnected to the left half portion of the 6SN7 input tube of theelectrical system shown at 22 to provide a triode oscillator. As viewedin FIGURE 6, this input tube is the left-hand tube within the dash linebox, and the specific connections to this tube from the sensing heads20' and cables 64 will be set forth later in this description.

As a general statement of the operation of the sensing heads 20 andassociated electrical system 22' shown within the dash line box ofFIGURE 6, it can be said that under normal conditions, that is, withouta conductive object to be sensed near the heads 20, the oscillatorcircuit, which includes the portion of the input tube 6SN7 together withthe associated wound inductance of sensing heads 20 and the distributivecapacity cables 64, oscillates continuously and the output thereof isamplified by the right-hand portion of the 6SN7 input tube and thesecond 6SN7 tube of the circuit. These amplified oscillations arerectified by the germanium diode shown at 76 to apply a sufficientnegative bias potential to the grids of the 6SN7 ouput amplifier tubeshown at the right-hand side of the dash line box of FIGURE 6. Thisnegative bias is sufficient to cut off this stage. However, when a massof conductive material, such as a steel ball, is introduced into thefield of the inductance within the head 20', the eddy current lossesoccurring therein serve to dampen or squelch the oscillations of thecircuit and thereby remove the bias from the output portion of theelectrical system. This permits a substantial current flow therethroughwhich can be utilized to operate desired means. In this case, thedesired means include a relay arrangement which will be described indetail later.

Turning now to FIGURE 6, it can be seen that terminal strip 66 has eightterminal connections which, for convenience, I have labeled 1' to 8',inclusive, as viewed from left to right on the drawing. The output ofthe voltage regulator 68 is fed through line 78 to terminal 4 andthrough line 80 to terminal 5. Terminal 4 is also connected to terminal6' by lie 82. From terminal 4', line 84 runs to a switch generallyindicated at 86 that is also connected to line 88 running to one side ofthe primary coil 90 of transformer 92. Line 94 runs from terminal 5 tothe other side of the primary coil 90. It will also be noted that leadsXX from lines 88 and 94 are connected at X'X' to leads 96 and 98. Lead98 is connected to one side of coil 100 of the two-way contact relay,generally indicated at 102. The other side of coil 100 is connectedthrough line 104 to contact 106 of a latching relay generally indicatedat 108. The lead 96 is connected to the movable contact arm 112 oflatching relay 108 which rests against contact 114 of the relay whenthis relay is unenergized. There is no operative connection to thiscontact 114.

Turning now to the transformer 92, secondary coil 116 is a low voltagewinding to provide filament voltage for the three tubes of the sensingmeans 22. The high voltage secondary coil 118 of transformer 92 isconnected to a rectifier and filter circuit designed to deliver a highvoltage D.C. supply to the sensing means 22 and relay 108. This circuitis conventional and will not be described in detail. One lead of thehigh voltage D.C. supply from.

the rectifier is grounded as at 120 while the other lead 122 isconnected to one side of coil 124 in relay 108. The other side of coil124 is connected by lead 126 to plates 128 and 130 of the output tube ofthe sensing circuit 22.

Terminal 1' of the terminal strip 66 receives the connection of theshielded cable and, as indicated, the connection is grounded. Terminals3' and 2' receive the two leads from the inductance coils in each of theheads 20. As indicated in FIGURE 6, terminal 2 is connected by lead 132to the grid 134 of the oscillator portion of the input tube 6SN7 shownat the left-hand portion of the dash line box. Terminal 3' is connectedby lead 136 to the cathode 138 of the same oscillator tube.

Referring again to relay 102, it can be seen that the movable contactarm 140 is connected through lead 142 to terminal 6' on terminal strip66, that contact 144 is connected through lead 146 to terminal 7 andthat contact 148 is connected through lead 150 to terminal 8'. As shownin FIGURE 6, terminal 6' is connected through lead 82 to terminal 4' andto line 78 of the AC. voltage supply. Terminal 7' is connected by lead154 to indicating light 26 and the other side of the indicating light 26is connected through lead 156 to the line 8 0 of the alternating currentsupply. Terminal 8' is connected through lead 158 to a rectifier circuitgenerally indicated at 160 which is designed to rectify and filter the110 volt A.C. supply to a 6 volt D.C. supply. As also indicated inFIGURE 6, line 80 of the A.C. circuit is. connected to this rectifier160.

At this point mention should be made of the counter or timer shown at24. This timer is commercially available, and for my use I have selecteda timer known as the Model S'1 produced by the Standard Electric TimeCompany of Springfield, Massachusetts. However, any suitable timer canbe used if desired and if operable within the scope of my invention. Thetimer 24 shown in the drawings is driven by an AC. synchronous motorthrough a gear train to register elapsed time in seconds andonehundredths of a second. There is a 6 volt D.C. clutch arrangementdisposed between the motor and dials of the timer so that movement ofthe dial hands of the timer are initiated and stopped through theoperation of this clutch. As shown in FIGURE 6 of the drawings, thisclutch is connected through lines 162 and 164 to rectifier 160. Inaddition, it is desirable that the timing device as at 24 has a resetdevice so that the operator can reset to zero after each blood viscositytest.

At 166 in FIGURE 1, I have shown a small panel control board which ismounted on panel 15. On this control board electric switch 168 turns thesynchronous motor of the timer 24 off and on. Directly above switch 168there is a red light 170 so connected that, when switch 168 is in an onposition and the synchronous motor of timer 24 is running, the red light170 will be on. Switch 172 on the control board 166 is used to reset thetimer to zero'when desired. A third switch 174 is provided to connectand disconnect the 6 volt D.C. rectifier 160 with the timer clutch.

The sensing arrangement of my invention operates in the followingmanner. When a steel ball which is falling through the fluid passes theupper sensing head 20, the associated electrical system 22 functions inthe manner previously discussed so that there is a current flow throughthe latching relay 108. When this occurs, movable contact arm 112 oflatching relay 108 is snapped and held against contact 106- of thelatching relay. At this time the circuit from the 110 volt A.C. supplyat XX' is completed through lead 98,. coil 100, line 104, contact 106,movable contact arm 112, and lead 96. As the coil 100 is energized,movable contact arm 140 is moved from contact 144 to contact 148. The.position of the movable contact arm 140 against contact 144 is thenormal or unenergized position of the arm when coil 100 is notenergized. In this normal position it can be seen that one side of theAC. circuit from terminal 6' is completed through lead 142, movablecontact arm 140, contact 144, and lead 146 to terminal 7'. From terminal7, lead 154 goes to one side of the indicating light 26 and the otherside of the indicating light 26 is connected through lead 156 to line 80or the other side of the alternating current circuit. Thus, in thenormal position illustrated in FIG- URE 6 of the drawings, theindicating light 26 will be energized and lit.

When the movable contact arm 140 is snapped to contact 148, one side ofthe alternating current from terminal 6' is now connected through lead142, movable contact arm 140, contact 148 and lead 150 to terminal 8 onthe terminal strip 66. From terminal 8' this side of the alternatingcurrent circuit continues through lead 158 to the 6 volt D.C. rectifierand filter supply generally indicated at 160. Line 80, the other side ofthe alternating current circuit, is also connected to this rectifier andfilter 160.

Therefore, as the steel ball passes the upper sensing head 20, relays108 and 102 operate so that the alternating current supply is shut oflfrom indicating light 26 and. is directed to the rectifier and filterarrangement to provide a 6 volt D.C. supply. As relay 108 is a latchingrelay, the current through coil 100 is maintained and a 6 volt D.C.supply is furnished to lines 162 and 164. If switch 174 on control board166 has been closed by the operator, the 6 volt D.C. clutch on timer 24will be energized and the hands on the timer 24 will start to move.

This condition prevails until the steel ball, which is falling throughthe column of blood, reaches the lower sensing head 20. At this timelatching relay 108 will again be operated in the manner described above,and movable contact arm 112 will be snapped from contact 106. to contact114. This interrupts the volt A.C. supply to coil 100 of relay 102 sothat movable contact arm will be snapped from contact 148' to contact14.4. At this instant the 6 volt D.C. supply will be interrupted to thetimer clutch to stop the movement of the hands of the timer 24. At thisinstant also, the indicating light 26 will again be energized.

What I claim is:

1. Apparatus for measuring the viscosity of a fluid comprising incombination, a tube, means for supporting said tube in a perpendicularlydisposed position, said tube being designed to receive the fluid to bemeasured, a ball feeder secured to and closing the upper end of saidtube, said ball feeder having hopper-like openings therein for holding aplurality of metallic balls, manually operated means disposed in saidball feeder adjacent said hopper-like openings to selectively receive anindividual ball from said hopper-like openings, said manually operatedmeans being movable to a predetermined ball release position, said ballrelease position being over the central portion of the column of fluidin said tube so that as the ball is dropped into the fluid the relativeflow of the fluid past the ball during the downward passage of the ballthrough the column of fluid will be through an annular aperture ofsubstantially constant area as defined by the size of the ball and theinside dimension of the tube, electrical sensing heads mounted on saidtube in vertically spaced relationship to detect the passage of a ballpast the respective sensing heads, said electrical sensing heads beingconnected through amplifier means to relay means which are adapted toinitiate and terminate the operation of timing means in response tosignals produced by the passage of said ball past an adjacent pair ofsaid electrical sensing heads.

2. Apparatus for measuring viscosity of a fluid comprising incombination, a tube having an opening at the bottom portion thereofthrough which the fluid to be measured can be inserted into the tube,means for closing said opening, a ball feeder mounted upon and closingthe upper end of said tube and having hopper-like openings therein forholding a plurality of metallic balls, manually operated means disposedin said ball feeder adjacent said hopper-like openings to selectivelyreceive an individual ball from said hopper-like openings, said manuallyoperated means being movable to a predetermined position where said ballis dropped into the central portion of the column of fluid in said tube,means for mounting the tube in a perpendicular position on a supportingstructure so that as the ball falls under the influence of gravitythrough the column of fluid the relative movement of said fluid pastsaid ball is through an annular aperture of substantially uniform size,electrical sensing means mounted in vertically spaced relationship onsaid tube, means connected to said sensing means to receive electricalsignals from the sensing means generated by the presence of said ball inthe area adjacent the respective sensing means, electrical timing meansconnected to said signal receiving means, said electrical timing meansbeing actuated and stopped in response to electrical signals from saidelectrical sensing means.

3. Apparatus as set forth in claim 2 wherein the viscosity tube has abulb-like enlargement therein adjacent the top of the tube into whichthe top of the column of fluid will extend during the measuringoperation.

4. Apparatus as in claim 2 wherein a portion of the bottom of said tubeis turned upwardly at an acute angle to provide a trap for air bubblesso that as the fluid is inserted the perpendicular column of fluid willnot tain air bubbles.

9 10 5. The combination set forth in claim 2, said tube being 2,388,38711/1945 Cohen 7357 X of definite inside diameter and said balls being ofa 2,731,828 1/ 1956 a rett 61 aldiameter approximately 1.83 mm. lessthan the diameter 2,955,459 10/1960 e ka e aL 73-57 of the tube.3,026,716 3/ 1962 Connally 73-57 5 3,073,151 1/1963 Fann 7354 ReferencesCited by the Examiner FOREIGN PATENTS UNITED STATES PATENTS 863,5103/1961 Great Britain. 1,247,523 11/1917 Flowers 73-57 34,163 1/1886Germany. 1,519,609 12/1924 Field 73439 Cline 10 C. Primary Examiner.

2,252,572 8/1941 Lang 73--57 DAVID SCHONBERG, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,240,053 March 15, 1966 John H. Jones It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

Column 1, before line 7, insert the following paragraph:

This application is a continuation-in-part of my copending applicationSerial No. 168,936, filed January 26, 1962, now abandoned, forimprovements in Viscosimeter.

column 2, line 28, for "specimens" read specimen column 3, line 7, after"11.72 sq. mm." insert a closing parenthesis; line 56, for "viscisity"read viscosity line 66, for "mean" read means column 6, line 24, for"lie" read line Signed and sealed this 24th day of January 1967.

(SEAL) Attest I ERNEST W. SWIDER EDWARD J. BRENNER Attesting OfficerCommissioner of Patents

1. APPARATUS FOR MEASUREING THE VISCOSITY OF A FLUID COMPRISINGINCOMBINATIN, A TUBE, MEANS FOR SUPPORTING SAID TUBE IN APERPENDICULARLY DISPOSED POSITION, SAID TUBE BEING DESIGNED TO RECEIVETHE FLUID TO BE MEASURED, A BALL FEEDER SECURED TO AND CLOSING TH UPPEREND OF SAID TUBE, SAID BALL FEEDER HAVING HOPPER-LIKE OPENINGS THEREINFOR HOLDIG A PLURALITY OF METALLIC BALLS, MANUALLY OPERATED MEANSDISPOSED INSAID BALL FEEDER ADJACENT SAID HOPPER-LIKE OPENINGS TOSELECTEIVELYRECEIVE AN INDIVIDUAL BALL FROM SAID HOPPER-LIKE OPENINGS,SAID MANUALLY OPERATED MEANS BEING MOVABLE TO A PREDETERMINED BALLRELEASE POSITION, SAID BALL RELEASE POSITION BEING OVER THE CENTRALPORTION OF THE COLUMN OF FLUID IN SAID TUBE SO THAT AST HE BALL ISDROPPED INTO THE FLUID THE RELATIVE FLOW OF THE FLUID PAST THE BALLDURING THE DOWNWARD PASSAGE OF THE BALL THROUGH THE COLUMN OF FLUIDWILLB E THROUGH AN ANNULAR APERTURE OF SUBSTANTIALLY CONSTANT AREA ASDEFINED BY THE SIZE OF THE BALL AND THE INSIDE DIMENSION OF THE TUBE,ELECTRICAL SENSING HEADS MOUNTED ON SAID TUBE IN VERTICALLY SPACEDRELATIONSHIP TO DETECT THE PASSAGE OF A BALL PST THE RESPECTIVE SENSINGHEADS, SAID ELECTIRCAL SENSING HEADS BEING CNNECTED THROUGH AMPLIFIERMEANS TO RELAY MEANS WHICH ARE ADAPTED TO INITIATE AND TERMINATE THEOPERATION OF TIMING MEANS IN RESPONSE TO SIGNALS PRODUCED BY THE PASSAGEOF SAID BALL PAST AN ADJACENT PAIR OF SAID ELECTRICAL SENSING HEADS.